Unable to build a simple Elixir project

Question

I worked my way through Dave Thomas' Elixir Programming. Now I hit the point where you created your first mixing project. HTTPoison has just been introduced and added to the application function in mix.exs. The project should now be compiled using iex -S mix. At that moment I had problems with ssl_verify_hostname. After installation erlang-srcand erlang-devnow I'm stuck in the next release of the console

$ iex -S mix
Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [kernel-poll:false]

WARN:  Expected /home/..../issues/deps/idna to be an app dir (containing ebin/*.app), but no .app found.
WARN:  Expected /home/..../issues/deps/ssl_verify_hostname to be an app dir (containing ebin/*.app), but no .app found.
==> hackney (compile)
WARN:  Expected /home/..../issues/deps/idna to be an app dir (containing ebin/*.app), but no .app found.
WARN:  Expected /home/..../issues/deps/ssl_verify_hostname to be an app dir (containing ebin/*.app), but no .app found.
Dependency not available: idna-.* ({git,
                                       "https://github.com/benoitc/erlang-idna",
                                       {tag,"1.0.2"}})
Dependency not available: ssl_verify_hostname-.* ({git,
                                                   "https://github.com/deadtrickster/ssl_verify_hostname.erl",
                                                   {tag,"1.0.5"}})
** (ArgumentError) argument error
    (stdlib) :io.put_chars(#PID<0.26.0>, :unicode, <<69, 82, 82, 79, 82, 58, 32, 99, 111, 109, 112, 105, 108, 101, 32, 102, 97, 105, 108, 101, 100, 32, 119, 104, 105, 108, 101, 32, 112, 114, 111, 99, 101, 115, 115, 105, 110, 103, 32, 47, 104, 111, 109, 101, 47, 114, 107, 114, 97, 117, ...>>)
    (mix) lib/mix/shell.ex:78: Mix.Shell.do_cmd/2
    (mix) lib/mix/tasks/deps.compile.ex:161: anonymous fn/5 in Mix.Tasks.Deps.Compile.do_command/4
    (mix) lib/mix/project.ex:196: Mix.Project.in_project/4
    (elixir) lib/file.ex:1061: File.cd!/2
    (mix) lib/mix/dep.ex:137: Mix.Dep.in_dependency/3
    (mix) lib/mix/tasks/deps.compile.ex:160: Mix.Tasks.Deps.Compile.do_command/4
    (mix) lib/mix/tasks/deps.compile.ex:59: anonymous fn/3 in Mix.Tasks.Deps.Compile.compile/1

Although I searched for different parts of this conclusion, I cannot find any useful information.

Answer 1

You must install all the dependencies before running the code.

mix deps.get (it loads dependencies)

mix deps ( )